1. Field of the Invention
The invention relates to a drive unit for a vehicle equipped with an electric motor.
2. Description of Related Art
A drive unit for an electric vehicle or a hybrid drive unit has been adopted as a drive unit for a vehicle, in which an electric motor is used as a drive source. A similar drive unit has been disclosed in Japanese Patent Laid-Open No. 2001-187535, in which an engine, a generator, and a gear train, which is drive-connected to a wheel through a differential unit, are connected through a planetary gear set. Power can thus mutually transmit among the engine, the generator, and the wheel. Accordingly, the drive unit can freely execute driving of the generator by the engine, assist in the driving force and start the engine when the generator serves as the electric motor, and perform regeneration using an inertia power which is returned from the wheel to the planetary gear set through the differential unit.
In the aforementioned conventional art, the engine and the generator are aligned coaxially in a side-by-side manner with the planetary gear set coaxially interposed therebetween. Furthermore, the gear train has a dual shaft structure with an input shaft for connecting the engine with one element of the planetary gear set, and a counter output shaft for connecting the wheel with the other elements of the planetary gear set through the gear train and the differential unit. The input shaft and the output shaft are related in which the input shaft serves as an inner circumference and the output shaft serves as an outer circumference.